Friday, April 23, 1999 Published at 22:25 GMT 23:25 UKWorld: EuropeNato 'determined to prevail'Nato says it will target the heart of President Milosevic's regimeNato leaders have vowed to intensify the military and economic pressure on Yugoslavia, including imposing an oil embargo.

Meeting in Washington to mark the alliance's 50th anniversary, they said air strikes would continue until Yugoslavia met all their demands over Kosovo.

Overnight, alliance planes attacked the southern Serbian city of Nis. The authorities claimed that 26 missiles hit the city as jets attacked in two waves.

The commander of the civil defences said immense damage had been done. A factory and a railway shunting yard were reportedly hit, as were the waterworks and electricity power lines. Local sources said one civilian had been injured.

In the northern town of Novi Sad, the oil refinery was said to have been targeted again and the flames from Yugoslavia's burning oil supplies lit up the night sky.

Areas around the capital of Kosovo, Pristina, were reported to have come under heavy bombardment, with air attacks on Slatina airport and on the communications tower high on Goles mountain.

Oil embargo

Following Nato's inclusion of an oil embargo in its 17-point statement on Kosovo, the alliance is drawing up plans to search ships in the Adriatic to prevent oil and other vital supplies reaching Yugoslavia.

The Supreme Allied Commander, General Wesley Clark, is working out rules of engagement for approval by Nato members after differences emerged over whether to apply a naval blockade.

The US said the alliance should apply a stop-and-search operation, but the French President, Jacques Chirac, said that stopping ships at sea would violate international law.

Analysts said such an operation could also provoke a confrontation with Russia if Russian ships were boarded and resisted a search.

UN resolution

Nato said it would suspend action against Yugoslavia once Belgrade had "unequivocally accepted" its conditions.

Officials said Serb forces would have to withdraw to a "precise and rapid timetable"; Albanian refugees would also have to be allowed to return to Kosovo under the protection of an international force.

Nato said it would seek a UN resolution to back its demands.

Bombing criticism

However, alliance attempts to show a united front suffered from Italian and Greek criticism of the bombing.

Speaking during the Nato summit, Greek Prime Minister, Costas Simitis, said the air strikes had done nothing to end the expulsion of Kosovo Albanians and called for diplomatic efforts to find a solution.

The Italian Foreign Minister, Lamberto Dini, said he disapproved of the attack on Thursday night of the headquarters of Serbian Television, in which the Serbs said at least 10 people had died.

Nato was earlier rebuked by several Western media organisations for the raid.

However other alliance leaders defended the attack, saying Yugoslavia's state-run media played an essential part in promoting Yugoslav President Slobodan Milosevic's malign doctrine of ethnic superiority. They said such attacks were likely to continue.